A sanitary washing device retractably houses a water discharge nozzle for squirting wash water, and can be installed on a sit-down toilet bowl to wash user's “bottom” and the like with warm water. Such a sanitary washing device includes a water channel system therein. Hence, for maintenance and inspection purposes and for the purpose of avoiding freezing in cold climates, for instance, the water supply section of the sanitary washing device requires drainage. Patent Document 1 discloses a sanitary washing device including a water supply section which allows easy maintenance and inspection, such as cleaning of its strainer and water drainage.    Patent Document 1: JP-A-2001-132048 (Kokai)